Boiler tube and attachment therefor



Jan. 19, 1932. A. D. FEST BOILER TUBE AND ATTACHMENT THEREFOR Filed Jan. 31. 1927 Patented Jan: 19, 1932 PATENT OFFICE ADOLPE D. FEST, F CHICAGQILLIN'OIS BOILER TUBE AND Arrrncnmnnr THEREFOR Application filed January 81, 1927. I, Serial No. 164,684.

These improvements relate to boiler tubes and tube attachments, with more particular reference to their application in what are known as water-tube boilers in which the tubes are closely arranged and respectively have a substantially long horizontal component. Y

The prime object of the invention is to provide means in connection with the tubes of such boilers for increasing the efliciency of the boiler through lessening the deposit of soot on the tubes. It is an object to provide an attachment device whereby the results mentioned may be attained in boilers 1 having tubes therein of standard construction and circular in cross view. Another object is to rovide, in the same construction or device or accomplishing the above-named results, deflecting and confining means for the furnace gases whereby the efficiency of the boiler is increased. It is an object, further, with respect to the attachment or analogous feature, to provide means whereby heat units may be accumulated in a device closely adj acent to the tubes respectively and thus conserve such units for beneficial effects. It is an object to attain the said results by simple means, and, with respect to the attachment feature, by means which may be applied to boilers already installed.

Other objects and advantages will appear hereinafter.

In the accompanying drawings, Figure 1 is a fragmentary vertical section through a water-tube boiler showing in cross-section several different embodiments of my present invention, these various embodiments being susceg tible of conjoint use in the same boiler; ig. 2 is a fragmentary side view of one of the tubes of Fig. 1 having thereon a sootdefiecting attachment shown also in Fig. 1

Fig. 3 is a fragmentary side View of the preferred construction of tube where the in vention is applied in the original construction of the boiler. A sectional view of Fig. 3 is shown in Fig. 1; and Fig. 4 is a small sectional and broken view showing a water tube boiler in accordance with this invention.

The form of attachment device shown in connection with some of the tubes of Fig. 1 is now considered by me to be the best mode of carrying the invention into effect in connection with boilers already installed.

Water tube boilers employing the present invention or being of the kind to which the present tubes are applicable for the desired results have their tubes in spaced-apart relation and substantially filling the space normally occupied by the flames and gases of combustion, the tubes being freely exposed to such gases and flames. The tubes are so positioned as to have a substantially large horizontal component. For the most part such tubes are horizontally disposed, but in some instances they slant to some extent toward one end. They are arranged in what may be called closely adjacent tiers one above another.

A very serious objection to the most advantageous functioning of such water-tube boilers is the accumulation of soot deposits on the upper surfaces of the tubes. The soot, containing tarry constituents, forms in a compact mass on these upper surfaces and usually in a short time produces a sooty upwardly-directed formation which is substantially pyramidal in cross view. I have found that when this pyramidal shape of the soot deposit has been reached the accumulative additions thereto are very slight since the additional deposits become subject both to the force of gravitation, causing them to slide off, and to the currents of air and gases in the furnace tending to 'blow them away. However, once the upper surfaces of these tubes become substantially well coated the soot acts as a good insulator to the furnace heat and the effectiveness of the tube is very much reduced. In practice it is necessary to remove the soot at fairly frequent intervals,

and where soft coal is used, as is. mostly the case, this operation is required more often than Where hard or semi-hard coal is employed.

Another difliculty arises from the fact that the tubes of such water-tube boilers are particularly hard to maintain clean, since it is diflicult to direct an air or steam blast upon the surfaces affected or to apply thereto a scraping tool; and the soot packs so tightly in the pyramidal formation mentioned that considerable force is required to break the structure down.

According to these improvements I provide a form of tube, either directly or by means of an attachment, whereby the surfaces upon which the soot falls have a pyramidal shape in cross view, a shape which very materially lessens, if not one which substantially overcomes the objection, and a shape, too, which lends itself to more advantageous cleaning operations should cleaning be desired. One important object thus realized is the avoidance of the frequent cleaning operations heretofore required.

Various cross-sectional forms of tubes, some including an attachment device, are shown in Fig. 1, and may be conjointly used.

In Fig. 1, the tubes 10 are originally formed with upwardly-slanting fiat sides 11 meeting in substantially as sharp convergence as ma conveniently be provided in practice. Suc a tube may be formed in suitable rolls from flat strip metal and the free edges thereof brought together and welded at any preferred place. Such tubes may be provided also by reforming cylindrical tubes into the rounded bottom and apical top shape shown. When the tube as 10 has such vertically-oblong shape throughout its length the openings in the boiler plate accommodating the tube ends will have the same shape. The preferred formation of at least one of the ends is shown in Fig. 3, where the tube 12 is shown as having cylindrical ends 12a. Such a tube may be formed with flat upwardly slanting and converging sides apical in cross view by reshaping a cylindrical tube by means of rolls or dies.

The tubes marked 15 are circular in cross view, according to the usual construction. On each of them is positioned an attachment 16, which is preferably of metal in order to conduct heat to the upper surfaces of the tubes 15 respectively. In practice castings of iron will be found satisfactory and cheap for the part 16. Each attachment 16 has a lower surface concave in cross view and so proportioned as to fit snugly upon the outer top surfaces of the tube. The cover 16 preferably extends downward sufliciently to overlie the upper half of the tube. The upwardly-converging sides 17 of the cover 16 are flat and meet in a point or apex at the top, in cross view. These attachments 16 may be long enough to extend from one end of the tube to the other, or they may be in sections. They may be held in place in any approved way as by bindin them at intervals with say iron wire 20 passing through slots as 21 (see tube 15a, Fig. 1), the wire ends being twisted together. Where the sections extend from end to end of the tubes a notched holding cleat as 23 engaging the attachment device (see tube 156 Fig. 1) may be applied to the end wall of the boiler. The sections may be interlocked as in Fig. 2, wherein one section 16 is shown as having a notch 25 while the other section 16 has an interfitting rojection 26. When so interlocked hol ing means are not necessary for each section. Various forms or types of interlocking means may be employed for the abutting sections. Where there is sufficient space for it notched cross bars 27 having their ends against the sides of the boiler, or against any suitable stop to prevent longitudinal movement, may be placed so that their notches engage the ridges of a plurality of the attachments, thus holding them in place.

A tube 15 with the attachment thereon may be considered to be a tube having a thickened upper wall substantially pyramidal or conical in cross view. Tube 30 shows such a thickened upper wall 31 having the pyramidal or conical formation integral with the rest of the tube. Such a tube could be formed by rolling or casting. In tube 32 the triangular ridge-like part 33 is to be considered as being separately formed and secured directly upon the upper surface of the tube 32 by a welding operation.

In the case of any of these latterly-described forms shown there is a considerable body of metal as 16 parts of which at least become considerably hotter than the tube proper, and this accumulated heat is retained within the body of the furnace for a substantially long period after the fire in the furnace has become low. This metal thus serves as a heat accumulator tending to stabilize and render more uniform the action of the boiler for water-heatin purposes un der varying conditions in the re box. Some of this accumulated heat is radiated to adjacent tubes while a large part of it is conducted directly to the tube with which the attachment, part or wall-enlargement is associated.

With respect to this upper formation, which is apical, conical, pyramidal or triangular in cross-section, the result is attained of preventing the accumulation of soot, first through the action of gravitation causing the soot to slide oif, secondly through the action of the air and gas currents in the furnace tending to blow them off, and thirdly through vibration tending to shake them loose. Even where they form upon the tubes of this invention they are substantially easily dislodged, as by tapping the tubes and thus jarring them loose. The scraping tool may also be a plied to those surfaces more easily and air lasts will reach these fiat surfaces with greater effect than they do the rounded up er surfaces of ordinary tubes. 1

he construction has a further advantage of constricting the passageways between adacent flues whereby furnace gases are caused wrought iron in practice, and cast iron would not be suitable for the purpose. The present invention is not directed to the mere provision of an apical top in or for a tube or hollow constructions that may be employed in some kind of a heater,but rather to the notable improvement 'in water tube boilers of the well-known kind in which the tubes are numerous and close together in spaced-apart relation and are directed so as to have a substantially long horizontal component. An improvement in this field along the lines herein specified has not been attempted otherwise than as herein disclosed so far as I am aware.

Fig. 4 shows several tiers of tubes in accordance with the present invention as applied to a water tube boiler, and according to which the water in, the boiler occupies the tubes as Well as the water jacketed space around the combustion chamber. The tubes in Fig. 4 may be considered to be in accordance with any of the specific embodiments shown in other figures.

I contemplate as being included in these improvements all such variations, changes and departures from what is thus specifically illustrated and described as fall within the scope of the appended claims. For example in the feature of the thickened upper wall i contemplate that in some instances this may be formed of finely divided metallic particles or of other suitable material blown or otherwise applied so as to assume a substantially pyramidal shape in cross view on the upper surfaces of the tubes.

I claim:

1. In a device of the class described the combination, with a water tube, of means for preventing the accumulation of material on the tube, said means comprising parts interlocked and attached to the tube to provide a deflecting surface substantially co-extensive with the length of the tube.

2. A water tube device having a plurality of heating tubes therein exposed to the products of combustion and being in substantially close arrangement with respect to each other,

each tube having a substantially long horizontal component and each tube having on its upper surface, substantially from end to end of that part thereof ex osed to the products of combustion, an attac ment structure comprising interlocked sections and being formed substantially to the shape of a body of soot normally deposited on such tube to the maximum extent, said maximum extent being that at which further deposits from the soot products of combustion will slide off.

ADOLPH D. FEST.

thereby re- 

